package leetcode.editor.cn;

public class Solution141 {
    public boolean hasCycle(ListNode head) {
        ListNode slow,fast;
        slow = fast = head;
        while (fast != null && fast.next != null){
            slow = slow.next;
            fast = fast.next.next;
            if (slow == fast){
                return true;
            }
        }
        return false;
    }
}
